Toothbrush

ABSTRACT

A head for an electric toothbrush having first and second brush parts, one of which is rotary and the other is reciprocally moveable or static. Preferred forms have elastomeric oral hygiene parts, and electric toothbrush heads with novel “V” sectioned oral hygiene parts are also disclosed.

TITLE OF THE INVENTION

This application claims the benefit of International Application NumberPCT/EP02/12879 filed Nov. 18, 2002.

This invention relates to toothbrushes, in particular to electrictoothbrushes, specifically to a brush head suitable for an electrictoothbrush.

BACKGROUND OF THE INVENTION

Electric toothbrushes generally comprise a handle which contains interalia a power supply and a drive motor, and a head which includes one ormore brush part bearing oral hygiene parts to be driven by the motor,generally in rotary motion about a rotation axis transverse to thehead—handle direction, and connected by a transmission means to themotor. The term “oral hygiene part” as used herein refers to a partwhich contributes to oral hygiene, for example by cleaning the teeth,gums or other oral tissues, and/or polishing the teeth, and/or massagingthe gums or other oral tissues. Often there is a neck between the handleand the head, and containing such a transmission means e.g. a driveshaft. Often the head is replaceable, typically being either replaceablyconnectable to the end of the neck remote from the handle, or beingintegral with the neck and the neck being replaceably connectable to thehandle at its end remote from the head.

Often the rotary motion is oscillatory, i.e. motion involving reciprocalangular displacement about a mean position. Sometimes the rotary motionalso involves a reciprocal back and forth movement of the brush partalong the rotational axis direction.

Numerous constructions of electric toothbrush are known, for example theapplicant's own Dr BEST “E-FLEX” (™) electric toothbrush launched in2000 which has a brush part mounted for oscillatory rotary motion. U.S.Pat. No. 6,000,083 discloses an electric toothbrush having both rotatingand static i.e. non rotating brush parts.

It is known from EP-A-0 990 424 (Procter & Gamble) to provide anelectric toothbrush having a motor-driven first brush part and a secondbrush part which is static, i.e. integrally made with the head andimmovable relative to the head. It is also known from EP-A-1 132 057(Unilever) to provide an electric toothbrush having bristle-bearingsegments linked flexibly to the head by means of a leaf hinge of aplastic material integral with the head.

Very often the oral hygiene parts comprise plural bristles arranged indiscrete tufts or mats on a surface of the brush part. Typically suchbristles are made of a nylon polymer e.g. the well known Tynex™. Oftenbristles are the only oral hygiene parts of a toothbrush. Toothbrusheshaving elastomeric oral hygiene parts on their head to contact the teethand gums are known.

Numerous types of elastomeric oral hygiene parts are known. GB-A-2 040161 discloses longitudinally extending elastomer strips. GB-A-2 214 420and WO-A-00/49911 both disclose a toothbrush having a head from whichproject small rubber pyramids. GB-A-214 701 discloses a toothbrushhaving oral hygiene parts comprised of strips of crepe rubber, in onetheoretically discussed embodiment of which the strips may have bristlessandwiched between the strips of crepe rubber. EP-A-0 360 766 disclosessmall rubber cylinders with knobbed ends. U.S. Pat. No. A-4,128,910discloses a toothbrush having rubber oral hygiene parts of variouspyramid and ridge shapes. U.S. Pat. No. A-4,277,862 discloses atoothbrush having resilient gum massage parts along the outer edges ofthe bristle pattern. U.S. Pat. No. A-4,288,883 discloses rubber cones.U.S. Pat. No. 5,040,260 discloses a toothbrush having a head from whichextend small rubber cones. WO-A-96/15696 discloses a toothbrush headprovided with strips of a flexible and resilient material, typically anon-elastomeric nylon material, and typically aligned eitherperpendicular to or parallel to the longitudinal direction.WO-A-96/28994 discloses elastomer bars extending perpendicular to thelongitudinal direction and parallel to the edges of the head incombination with bristle “bars” having an elongate cross section cutacross the bristle direction, and also discloses a curved rubber“scooping bar” at the tip end of the head. WO-A-97/16995 discloseselastomer “bristles”. WO-A-98/18364 discloses tooth polishing pads orfinger-like structures. WO-A-99/37181 discloses an outer ring of rubberfingers surrounding an inner dense pack of bristles. WO-A-00/64307discloses rubber bars with a generally triangular cross section.WO-A-00/76369 discloses elastomeric massaging parts with rotationalsymmetry through an angle of 120° or less e.g. cylinders. WO-A-01/21036discloses a longitudinally extending elastomeric wall-like memberrunning for at least half the length of the head.

Electric toothbrushes having elastomeric oral hygiene parts are known,e.g. WO-A-01/01817 discloses an electric toothbrush having a head withelastomeric fingers or arcuate lamellae mounted on it. EP-A-0 435 329discloses an electric toothbrush having interdental points in rubbermounted on it.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an electric toothbrushhaving improved ability to clean the teeth, particularly to adjustitself to a user's teeth. For example each user is likely to have adifferent spacing of interdental gaps between his/her teeth and it isdesirable for an electric toothbrush to be able to accommodate itself toany pattern of interdental gaps. It is a further object of thisinvention to provide an improved electric toothbrush having elastomericoral cleaning parts on its head.

In a first embodiment this invention provides a head for an electrictoothbrush which is connected to, or replaceably connectable to, ahandle which contains an electric motor, to provide a toothbrush havinga head-handle longitudinal direction, characterised in that the headhas:

at least one first brush part bearing oral hygiene parts and which isdriveable by the motor in rotary motion about a first rotation axisgenerally perpendicular to the longitudinal direction;

and at least one second brush part bearing oral hygiene parts, which isnot driven by the motor and is capable of limited reciprocallongitudinal motion, or limited reciprocal motion along a directiongenerally perpendicular to both the longitudinal direction and to thefirst rotation axis, or limited reciprocal rotary motion about a secondrotation axis generally parallel to the first rotation axis.

In this first embodiment the oral hygiene parts may be exclusivelybristles.

Alternatively in this first embodiment at least one of the first orsecond brush parts has oral hygiene parts being bristles mountedthereon, and at least one of the first or second brush parts has one ormore elastomeric oral hygiene part mounted thereon.

It is considered that an electric toothbrush head construction havingfirst and second brush parts, one of which is driveable by an electricmotor and is mounted on the head for rotation, and the other is statici.e. imoveable relative to the head, at least one of the brush partsbeing provided with elastomeric oral hygiene parts is also novel.

Therefore in a second embodiment this invention provides a head for anelectric toothbrush which is connected to, or replaceably connectableto, a handle which contains an electric motor, to provide a toothbrushhaving a head-handle longitudinal direction, characterised in that thehead comprises first and second brush parts,

at least one of the first or second brush parts being driveable by themotor in rotary motion about a first rotation axis generallyperpendicular to the longitudinal direction,

the other of the first or second brush parts being static,

at least one of the first or second brush parts having bristles mountedthereon,

at least one of the first or second brush parts having one or moreelastomeric oral hygiene part mounted thereon.

DETAILED DESCRIPTION OF THE INVENTION

The term “head” as used herein comprises the bristle-bearing part of thetoothbrush. Generally the head will extend integrally toward the handleas a neck. Generally the head will include a suitable mounting for abrush part which is mounted or mountable on the head for rotation, orfor limited reciprocal motion (in those embodiments of this inventionwhich include such a brush part).

The term “elastomeric” as used herein includes both natural rubbers andsynthetic elastomer materials, preferably thermoplastic elastomermaterials. Preferably the elastomeric material has a hardness from about10 to about 90 Shore A, more preferably 50 Shore A or less, e.g. fromabout 14 to about 35 Shore A. Suitable elastomeric polymers includestyrenes (for example styrene ethylene butadiene styrene, or styrenebutadiene styrene), and silicone elastomeric materials may also be used.Suitable elastomeric materials include those available under the tradenames Megol and Santoprene. Manual (i.e. non-powered) toothbrushes areknown with elastomeric oral hygiene parts, and the elastomeric materialsused for these are likely to be suitable for the elastomeric oralhygiene parts of the toothbrush heads of this invention.

Preferably in both the first and second embodiment there is only onefirst brush part and only one second brush part.

Preferably in both the first and second embodiment the first and secondbrush parts are relatively longitudinally disposed along the head-handledirection.

Preferably in both the first and second embodiment there is a firstbrush part furthest from the handle, and a second brush part adjacent tothe first brush part and closer to the handle (in the assembledtoothbrush) than the first brush part.

Preferably in both the first and second embodiment a first brush partfurthest from the handle is mounted or mountable for rotation on thehead about a rotation axis perpendicular to the head-handle direction.Such a first brush part may be mounted for rotation in an otherwiseconventional manner, and may be driven in rotational motion in aconventional manner via a motor. Such a motor-driven first brush part issuitably circular about the first rotation axis, and suitably the rotarymotion of the first brush part is limited reciprocal rotary motion.

The term “rotary motion” used herein includes limited reciprocal rotarymotion, i.e. rotary motion through an angle less than 360° in a firstrotary direction, followed by rotary motion through the same angle asthe opposite rotary direction. Suitably the angle is less than 180°,preferably less than 90°.

Preferably in both the first and second embodiments only one of thefirst or second brush parts is mounted for rotation, especially a firstbrush part at the end of the head remote from the handle.

Preferably in the first embodiment the second brush part, preferably asecond brush part longitudinally adjacent to this first brush part andcloser to the handle, is capable of limited reciprocal longitudinalmotion.

A second brush part may be enabled to perform limited reciprocal motionby means of end-stop abutment parts on respectively the head and on thesecond brush part, which abut when the second brush part reaches theends of its limited reciprocal motion, to thereby limit the reciprocalmotion.

For example when the second brush part performs limited reciprocallongitudinal motion the head may comprise a rail part along which thesecond brush part may slideably longitudinally move, and the secondbrush part may have one or more part, e.g. a pin or slider which canmove longitudinally along one or more corresponding guide, slot orgroove in the head e.g. in the rail part, the opposite longitudinal endsof the guide, slot or groove comprising the end-stop means. In apreferred construction the second brush part has pins or sliders onopposite longitudinal sides which slideably engage in respectivelongitudinal guides, grooves or slots in opposite sides of the head. Forexample the second brush part may comprise a saddle of substantially “C”shaped cross section across the longitudinal direction which an sitlongitudinally slideably upon the head, and the ends of the “C” comprisesliders, which slideably engage in respective longitudinal guides,grooves or slots in opposite sides of the head. By making the secondbrush part, or at least such pins or sliders resilient, e.g. of aresilient plastics material such as polypropylene, polystyrene etc. andof suitable dimensions which will be apparent to those skilled in theart, such a “C” sectioned structure can snap fit into the slots and beretained on the head.

In an alternative construction for example the second brush part mayhave a longitudinal channel which can run along a longitudinal rail partof the head, for example threaded longitudinally through the channel.Such a rail part and channel may have end-stop abutment parts to permitlimited longitudinal relative movement of the second brush part and headpart.

Similarly when the second brush part is constructed to perform limitedreciprocal motion in a direction generally perpendicular to thelongitudinal direction the second brush part and head part may have asimilar pin or slider and slot or groove, or a channel and rail part,but aligned generally perpendicular to the longitudinal direction, withend-stop means analogous to those described above.

Preferably in the second embodiment the static second brush part may bemade integrally with the head.

Preferably in both the first and second embodiments both of the firstand second brush parts have bristles mounted thereon, extending from abristle face thereof. At least one of the first and second brush parts,of either of the first and second embodiments, may (and in the case ofthe second embodiment does) have at least one elastomeric oral hygieneelement thereon. In a preferred construction a first brush part mountedfor rotation and furthest from the handle has bristles but noelastomeric cleaning parts mounted thereon, and a second brush partcloser to the handle has both bristles and elastomeric cleaning partsmounted thereon.

Bristles on the first and/or second brush parts may extend generallyperpendicular to the longitudinal direction and to the bristle face.Alternatively the bristles may be aligned at a non-perpendicular angleto the surface of the brush part from which they extend, e.g. nonperpendicular relative to the longitudinal direction, e.g. leaningtoward or away from the handle. On a first brush part mounted forrotation the tufts of bristles may lean in a manner as disclosed inPCT/EP01/14040 the contents of which are incorporated herein byreference. For example widthways separated tufts of bristles, especiallyon a non-rotating second brush part, may lean in respective oppositesuch directions so that as seen looking widthways the widthwaysseparated tufts are seen to cross e.g. in an ‘X’ shape. Such a bristlearrangement is well known, e.g. from inter alia U.S. Pat. No. 3,085,273and U.S. Pat. No. 5,274,873 etc. The bristles may all be the samelength, or tufts may differ in length, for example longitudinallyadjacent tufts alternating between two different relatively longer andrelatively shorter lengths, for example as disclosed in DE-A-44 09 395.

The one or more elastomeric oral hygiene part may be of known type, forexample as disclosed in the art discussed above, e.g. one or more of theknown small rubber cones, small rubber pyramids, strips of rubber,elastomer “bristles”, tooth polishing pads, finger-like structures,elastomer bars e.g. of a generally rectangular cross section,elastomeric massaging parts with rotational symmetry through an angle of120° or less, cylinders, a resilient elastomer wall-like member, smallrubber cylinders with knobbed ends, elastomeric fingers or arcuatelamellae, interdental points in rubber etc.

A preferred type of elastomeric oral hygiene part comprises anelastomeric strip extending in its length dimension from the brush part,particularly from a second brush part closer to the handle than a firstbrush part, having a width dimension perpendicular to its lengthdirection, and a thickness dimension perpendicular to both the lengthand width directions, the thickness dimension being less than the widthdimension. Typically the length of such a strip may be generally thesame as or less than the length of conventional toothbrush bristles, thewidth may be in the range ca. 0.1-0.25 of the length dimension, and thethickness dimension may be ca. 0.1-0.25 of the width dimension.

The width direction of such one or more strip may be alignedperpendicular or parallel to the head-handle direction, or may bealigned at a non-zero, non-perpendicular angle to the handle-headdirection and such an alignment may be either so that the edge of thestrip closest to the handle is inward or outward relative to theopposite edge. If a plurality of such strips is present, then the stripsmay be aligned at a variety of angles to the head-handle direction.

A preferred embodiment of such strips is for a pair of such strips to beadjacent, preferably longitudinally adjacent, and for such adjacentstrips to converge such that their respective width dimensions form a“V” shape. In a particularly preferred embodiment a pair of suchadjacent, preferably longitudinally adjacent, strips is integrallyformed as an integral strip of a “V” shaped cross section as cut acrosstheir length direction. The point of such a “V” may point outwardly orpreferably inwardly relative to the longitudinal head-handle. Typicallythe “V” may enclose an angle of 45°-90°, e.g. 55°-65°.

The one or more elastomeric oral hygiene part may be positioned anywhereon the first and/or second brush part, but preferably around thesideways edges of a head part, e.g. a second brush part, so that it/theycan massage the gums. It is preferred that plural elastomeric oralhygiene parts are arranged along each of the sideways edges of a secondbrush part which is closer to the handle than a first brush part. It isparticularly preferred that plural of the above-mentioned “V” sectionedelastomeric oral hygiene parts are positioned around each edge of asecond brush part.

A particularly preferred form of the toothbrush head of the firstembodiment of this invention therefore comprises:

a first brush part furthest from the handle mounted or mountable on thehead for rotation about a rotation axis perpendicular to the head-handledirection,

a second brush part longitudinally adjacent to this first brush part andcloser to the handle, which is capable of limited reciprocallongitudinal motion,

the first and second brush part having oral hygiene parts comprisingbristles mounted thereon.

Another particularly preferred form of the toothbrush head of the firstembodiment of this invention therefore comprises:

a first brush part furthest from the handle mounted or mountable on thehead for rotation about a rotation axis perpendicular to the head-handledirection,

a second brush part longitudinally adjacent to this first brush part andcloser to the handle, which is capable of limited reciprocallongitudinal motion,

the first and second brush part having oral hygiene parts comprisingbristles mounted thereon,

and the second brush part having both bristles and at least oneelastomeric cleaning part mounted thereon,

the elastomeric oral hygiene part comprising an adjacent pair ofelastomeric strips with their width directions converging to define a“V” shaped cross section between them as cut across the lengthdirection, the point of the “V” pointing inwardly relative to thelongitudinal head-handle direction.

In this preferred form of the first embodiment of the toothbrush of theinvention the plural elastomeric strips are preferably positioned aroundthe edge of the second brush part.

The elastomeric oral hygiene part(s), e.g. such strips of elastomericmaterial, may extend to the edge of the brush part, and preferablyslightly beyond. The elastomeric material of the oral hygiene part(s)parts may be continued around the edge of the brush part and down thesides of the brush part for example to provide gum massaging parts or abuffer against excessive impact with the oral tissues, especially withthe buccal surfaces.

It is believed to be novel to provide an electric toothbrush head withan elastomeric oral hygiene part of the above-described type comprisinga pair of elastomer strips converging such that their respective widthdimensions form a “V” shape, e.g. integrally formed as an integral stripof a “V” shaped cross section as cut across their length direction. Sucha head comprises a third embodiment of this invention.

For example such a head of this third embodiment may comprise a head foran electric toothbrush which is connected to, or replaceably connectableto, a handle which contains an electric motor, to provide a toothbrushhaving a head-handle longitudinal direction, the head having at leastone brush part bearing at least one oral hygiene part and which isdriveable by the motor in rotary motion about a rotation axis generallyperpendicular to the longitudinal direction characterised in that:

the brush part carries an oral hygiene part comprising an elastomericstrip which in section as cut across the rotation axis is elongatedalong a long dimension which is aligned at a non-zero, non-perpendicularangle to a radius from the rotation axis.

Preferably the elastomeric strip of this third embodiment of theinvention extends in a strip length direction which is substantiallyaligned with the rotation axis.

Preferably the cross section of the elastomeric strip of this thirdembodiment of the invention is elongated in a straight line, and itssection preferably has substantially parallel opposite long sides.

Preferably of this third embodiment of the invention the long dimensionof the section is aligned at an angle between 10°-80° to the radius,more preferably between 30°-60°, e.g. ca. 45° to the radius.

Preferably in this third embodiment of the invention the brush partcarries plural elastomeric strips, preferably arranged on thecircumference of a circle centred on the axis of rotation. There may beone or more such circle, preferably concentric, each having elastomericstrips arranged around it. For example there may be 6-20 such strips,e.g. 10-16.

In a preferred form of this third embodiment of the invention, pairs ofthe elastomeric strips are arranged such that the alignment of the longdimensions of elastomeric strips adjacent to each converge toward a “V”or chevron shape. Preferably such pairs of elastomeric strips arearranged around a circle centred on the rotation axis. In such anarrangement the point of the “V” or chevron may point, preferablyradially, either inwardly toward or outwardly from the axis of rotation.However the point of the “V” or chevron may point around a circlecentred on the rotation axis. In a particularly preferred constructionthe adjacent edges of such converging adjacent elastomeric strips arejoined so that the pair of joined elastomeric strips forms a unitaryoral hygiene part with a “V” or chevron cross section cut across therotation axis.

In this third embodiment of the invention the angle between the limbs ofthe “V” or chevron may typically be in the range 30°-120°, for example60°-100°. Typically the angle of the “V” or chevron may be symmetricallybisected by a radius from the axis of rotation.

In this third embodiment of the invention typically there may be 5-12such “V” or chevron sectioned oral hygiene parts on the head.

In the head of this third embodiment of the invention the elastomericstrips may be combined in a cluster, centred on the rotation axis, withother oral hygiene parts such as tufts of bristles. For example theremay be plural elastomeric strips of which adjacent pairs are joined tocomprise a strip of unitary “V” or chevron cross section, arranged onthe circumference of a circle centred on the axis of rotation,surrounding an inner cluster comprising one or more ring or polygon oftufts. For example there may be one or more tuft circumferentiallybetween adjacent strips or the above-mentioned “V” section elements. Forexample there may be one or more tuft of bristles located in the “bite”of the “V” of such a convergent pair of strips. Suitably the circle ofelastomeric strips may be the radially outermost, from the rotationaxis, of the cleaning elements for example to enable the elastomericstrips to contact the user's gums.

The elastomeric strip(s) of all embodiments referred to herein mayextend from the face of the brush part for a length approximately thesame as that of bristles from the head of a conventional electrictoothbrush, e.g. typically 8-11 mm, or may extend for a greater orlesser distance than this. The long dimension of each strip, e.g. ofeach limb of the “V” of a joined adjacent pair, may be ca. 1-3 mm, andthe thickness between the long surfaces may for example be 0.1-0.5 mm.

An elastomeric oral hygiene part may be made by a process of injectionmoulding, in which a hard plastic material part of the brush part isformed first, and then the formed plastic part is enclosed in a mouldcavity defining the shape of the elastomeric oral hygiene part(s) to beformed, and the elastomeric material is injected into the mould in afluid state. Analogous processes to make toothbrushes with elastomericmaterial parts are well known.

Suitable drive mechanisms to drive the brush part of the toothbrushheads of this invention are known, for example in U.S. Pat. No.5,577,285 and the drive speeds, amplitudes, and oscillation frequencies,e.g. ca. 3000-6000 rpm achievable by means of such known drivemechanisms are believed to be suitable for the head part of the presentinvention.

Therefore the invention further provides an electric toothbrush having ahead part according to any of the first, second or third embodiments asdescribed above.

The head of this invention may be connectable, preferably replaceablyconnectable, to a toothbrush handle containing an electric drive motor.For this purpose the head part suitably has connection means by whichthe head part may be connected to the handle to thereby connect thebrush part to the motor. The head part may comprise a hollow neck partlongitudinally between the brush part and the handle and enclosing adrive shaft by which the motor can drive the brush part via suitabletransmission means, and the end of such a neck part closest to thehandle may itself be connectable, preferably replaceably, to the handlein a manner which also connects the drive shaft to the motor.Alternatively the brush part may itself be connectable, preferablyreplaceably, to the head part at its end remote from the handle. Manyalternative connection means, and means by which the motor can drive theshaft and the shaft drive the brush part are known.

The brush part and bristles if present of the head part of thisinvention may be made of materials which are conventional in the fieldof electric toothbrush manufacture, e.g. respectively of plasticsmaterials and nylon fibres. The plastics material parts of the bristlebrush part and other plastics material parts of the toothbrush may bemade by an injection moulding process.

The toothbrush head of this invention is connected to or replaceablyconnectable to a handle of the toothbrush which contains an electricmotor which may be conventional, driven by replaceable, non-replaceableor re-chargeable batteries, and a switch means to active the motor. Themotor may be connected to or connectable to the head by means of aconventional drive shaft and transmission unit, passing along agenerally longitudinal neck between the handle and body. The head andhandle may be integrally permanently connected, and such a toothbrushmay be disposable, e.g. once the batteries are drained the wholetoothbrush is thrown away. Alternatively the head may be replaceablyconnectable to the handle by any conventional form of connection such asa bayonet connection. The replaceable connection may be between the headand such a neck, or between such a neck and the handle. Numeroussuitable motors, drive shaft and transmission systems, batteries,switches etc. which can produce such rotary or oscillatory rotary motionare known from the literature and from commercially availabletoothbrushes, see for example U.S. Pat. No. 5,577,285, U.S. Pat. No.6,000,083, WO-A-01/06947, WO-A-96/37164 etc. The materials of the head,neck and handle of the toothbrush of this invention may be entirelyconventional in the field of toothbrush technology. The parts of thetoothbrush of this invention may be manufactured and assembled usingtechniques generally conventional to the art of toothbrush manufacture,e.g. using two-component injection moulding to manufacture plasticsmaterial parts and the elastomeric oral hygiene parts.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of non-limiting example only,with reference to the accompanying drawings which show:

FIG. 1 shows a side view of a head part of a toothbrush of the firstembodiment of this invention with occluded parts shown with dottedlines.

FIG. 2 shows a plan view of the head part of FIG. 1 looking down alongthe first rotation axis, with occluded parts shown with dotted lines.

FIG. 3 shows a cross section through the head part as shown in FIGS. 2and 3 cut along the line C-C of FIG. 1.

FIG. 4 shows a schematic overall side view of an electric toothbrush ofthe second embodiment of this invention.

FIG. 5 shows a cross section at line B-B through the head of FIG. 4.

FIG. 6 shows an alternative construction of the head of FIG. 4.

FIG. 7 shows a plan view of the head of FIGS. 4-6.

FIG. 8 shows a perspective view of the head of the electric toothbrushof FIGS. 1 to 7.

FIG. 9 shows another perspective view of the head of FIGS. 1 to 8.

FIG. 10 shows the overall layout of an electric toothbrush of the thirdembodiment of this invention.

FIG. 11 shows a plan view of a cluster of oral hygiene parts of thetoothbrush of FIG. 10

FIG. 12 shows a plan view of an alternative cluster of oral hygieneparts of the toothbrush of FIG. 10

FIGS. 13A, 13B and 13C show the geometric basis of FIGS. 11 and 12.

Referring to FIGS. 1, 2 and 3, a toothbrush head part 10 overallaccording to the first embodiment of this invention is shown. The headpart 10 is integrally made with a neck part 11, which is integrallyextended at its end 12 to form an integral handle (not shown). Thehandle contains a battery-powered electric motor and its batteries, withassembled switch means etc. for the user to operate the toothbrush. Thehead 10 and handle (not shown) lie along a longitudinal direction (A-A).Longitudinally passing along an internal channel 13 in the neck 11 is adrive shaft 14 by which a first brush part 20 mounted on the head part10 can be driven by the motor (not shown) within the handle.

The first brush part 20 is mounted at the end of the head part 10 remotefrom the handle. The first brush part 20 is mounted for limitedreciprocal motion about a first rotation axis B-B perpendicular to thelongitudinal direction A-A. Many suitable ways are known in the art bywhich the brush part 20 may be so mounted, as are suitable transmissionsystems between the drive shaft 14 and carrier 20. Bristles 21 extendfrom the first brush part 20 substantially parallel to axis B-B.

Mounted on the head part 10 adjacent to the first brush part 20 is asecond brush part 30, at the end of the head part 10 closest to thehandle. Extending from second brush part 30 are second bristles 31extending substantially parallel to axis B-B, i.e. substantiallyperpendicular to the longitudinal direction A-A. The second brush part30 is mounted for limited reciprocal longitudinal motion as follows, andis more clearly shown in FIG. 3.

The second brush part 30 is in the form of a saddle having alongitudinal channel 32 which can sit upon a generally correspondingpart 15 of the head part 10, which functions as a rail part. The secondbrush part 30 is consequently of generally a “C” shaped cross section.The second brush part 30 is also provided with slider parts 33 on itsopposite longitudinal sides which fit into corresponding longitudinalslots 16 respectively in opposite sides of head part 10. Slider parts 33can slide longitudinally along head part 10 within slots 16, and thelimits of longitudinal movement of the slider parts 33 is limited byabutment of the longitudinal ends of slider parts 33 against thelongitudinal ends of the slots 16.

It will be understood that there are other ways in which the brush part30 can be mounted for limited reciprocal longitudinal movement on headpart 10.

Those skilled in the art will appreciate that the brush part 30 may beassembled with head part 10 in various ways, for example the sides ofthe brush part 30 adjacent to sliders 33 may be resilient and able todeform outwardly, so that the slider parts 33 can be snap-fitted aroundhead part 15 into slots 16. Parts 10, 20, 30 may be made of resilientplastics materials commonly used in the toothbrush art.

As seen in FIG. 1 second bristles 31 alternate in longitudinalsuccession between two lengths, a longer length 31A and a shorter length31B.

In use, the motor is switched on, causing the first brush part 20 torotate in reciprocal rotary motion. The user then applies the toothbrushhead part 10 to the teeth, suitably using the known Bass technique inwhich the head part 10 is moved reciprocally longitudinally along theline of the teeth. Friction between the second bristles 31 and the teethcause the second brush part 30 to move reciprocally longitudinally inthe opposite direction to which the toothbrush head part 10 is moved, asshown by the arrows in FIGS. 1 and 2, between the limits of movementdefined by the longitudinal ends of the slots 16. It is found thatreciprocal movement of second brush part 30 with a maximum amplitude inthe range 0.5-1.5 mm, typically ca. 0.7 mm between the limits oflongitudinal motion is suitable.

Referring to FIGS. 4 to 9 an electric toothbrush 40 comprises a handle41 which contains inter alia a power supply such as a battery (notshown) and a drive motor (not shown), and a head 42, upon which ismounted a first brush part 43, which is disc-shaped to be driven by thedrive motor in rotary motion about a rotation axis A-A passing throughthe centre of the disc shape of brush part 43 transverse to thehead—handle direction, and connected by a transmission means (not shown)to the motor. There is a neck 44, integral with head 42 extending fromthe handle 41 and connected to the head 42 which internally contains thetransmission means. The head 42 is replaceable, being integral with theneck 44, the neck 44 being replaceably connectable to the handle 41 atits end 45 remote from the head 42. A cluster of tufts of bristles 46 ismounted on the first brush part 43, extending from a bristle surfacethereof facing generally in a bristle direction parallel to the axisA-A, with their ends closest to the brush part 43 set in the first brushpart 43 and their distal ends furthest from the head 42. The bristles 46are the only oral hygiene parts on the first brush part 43. The rotarymotion about axis A-A is oscillatory, i.e. motion involving reciprocalangular displacement about a mean position.

Longitudinally immediately adjacent to first brush part 43 is a secondbrush part 47, such that the first brush part 43 is furthest from thehandle 41, and the second brush part 47 is closer to the handle 41 thanthe first brush part 43. The second brush part 47 is substantiallysemi-oval or cresecentic in plan looking down the bristle direction.

The second brush part 47 is mounted on the head 42 so as to be capableof limited reciprocal longitudinal motion of a longitudinal amplitudeca. 0.5 mm-1 .5 mm, typically ca. 0.7 mm, along the head-handledirection. The overall construction of the second brush part 47 issimilar to the second brush part 30 of FIGS. 1-3 and correspondingnumbering of parts is used. A cross section through the brush part 47 atline B-B of FIG. 4 is shown in FIG. 5.

The second brush part 47 also has tufts of bristles 50 mounted on itsupper surface, the bristles 50 being aligned parallel to the bristles 46on the first brush part 43. The second brush part 47 also haselastomeric cleaning parts 51 mounted thereon. Each part 51 comprises apair of elastomeric strips 51A, 51B extending in their length dimensionfrom the second brush part 47, each with a width dimension perpendicularto its length direction, and a thickness dimension perpendicular to boththe length and width directions, the thickness dimension being less thanthe width dimension. The length of the parts 51 is less by ca. 0.2-1 mmthan the length of the bristles 110. The pairs of strips 51A, 51B areintegrally made, and their width directions converge and meet such thattheir respective width dimensions form a “V” shape, and so that eachpart 51 is integrally of a “V” shaped cross section as cut across itslength direction, enclosing an angle ca. 60-90°. The “V”'s pointinwardly relative to the longitudinal head-handle direction.

The elastomeric oral hygiene parts 51 are arranged along each of thesideways edges of the second brush part 47. The edges of each of thestrips 51A, 51B extend to the edge of the second brush part 47 andslightly beyond. The elastomeric material of the parts 51 is continuedas a perimeter extension 52 around the edge of the second brush part 47,and down the sides of the second brush part 47 as projecting elastomericridges 53, for example to provide gum massaging parts or a bufferagainst excessive impact with the oral tissues. it is static andincapable of movement relative to first brush part 43. As shown in FIG.6 th e

FIG. 6 shows a cross section at line B-B of FIG. 4 of an alternativeconstruction of the toothbrush of the second embodiment of thisinvention. This construction may have an overall appearance andarrangement substantially identical to that shown in FIGS. 4-9 butinstead of being reciprocally longitudinally moveable the second brushpart 47 is fixed, i.e. second brush part 47 is made integrally with head42 e.g. by injection moulding.

Referring to FIG. 10 an electric toothbrush is shown overall in sideview 100. The toothbrush 100 comprises a handle 101 by which it may beheld, and which includes a drive motor, batteries, controls etc. (notshown). The handle 101 is replaceably connected at link 102, suitably abayonet connection, to a replaceable head part 103. The assembly ofhandle 101 and head part 103 are disposed along the length direction A-Aof the toothbrush 100. In the head part 103 is a brush part 104 mountedto be driven in oscillatory rotary motion around an axis B-B by themotor within handle 101. A conventional transmission mechanism, e.g. adrive shaft running along the head part 103 connects the motor to brushpart 104.

From a face 105 of brush part 104 a cluster of oral hygiene parts 106extend in a direction generally perpendicular to the length A-A. In usethe brush part 104 performs an oscillatory, i.e. reversing, rotarymotion about an axis of rotation parallel to bristle direction B-B andpassing through the centre in plan of the cluster 106, the amplitude ofthe oscillatory rotary motion being ca. 30° either side of a meanposition.

In FIG. 10 the head part 103 is shown as comprising a neck part 107between the brush part 104 and handle 101. In an alternativeconstruction (not shown) the neck part 107 may be integral with thehandle, and the brush part 104 may itself be replaceably connectable tothe neck part.

Referring to FIG. 11, a plan view of the cluster 106 is shown, lookingdown onto the upward facing surface 104 of brush part 105 in thedirection B-B. The brush part 105 is circular and the rotation axis B-Bof FIG. 1 passes through the centre of brush part 105.

The cluster comprises plural, six being shown, there may be more orless, oral hygiene parts 111 which are seen in section cut across therotation axis. As shown in FIG. 11 each element 111 itself comprises apair of rubbery strips 112 the cross section of each strip of which iselongated along a long dimension ‘L’ which is aligned at a non-zero,non-perpendicular angle to a radius from the axis of rotation andintersecting the strip. The respective long dimensions of the adjacentstrips 112 converge, and adjacent edges of strips 112 are joined at edge113 so that the pair of joined rubbery strips 112 forms the element 111of unitary “V” or chevron cross section. The elements 111, andconsequently the strips 112, are arranged on a circle centred on therotation axis B-B. In FIG. 11 the points of each of the “V” or chevronshaped sections points radially outwardly from the central rotation axisB-B.

Referring to FIG. 12 similar elements 121 are shown, again each element121 itself comprising a pair of rubbery strips 122 of which theirrespective long dimensions converge, and adjacent edges are joined atedge 123 so that the pair of joined rubbery strips 122 forms an element121 of unitary “V” or chevron cross section cut across the rotation axisB-B. However in FIG. 12 the points of the “V” or chevron points inwardlytoward the axis of rotation B-B.

The cross section of each of the strips 112, 122 making up the “V”section elements 111, 121 is elongated in a straight line, and thesection has substantially parallel opposite long sides terminating atshort edges 114.

As shown the long dimension of the section of each strip 112, 122 isaligned at an angle ca. 45° to radii intersecting the strip.

On the brush part 105 the elastomeric oral hygiene parts 111, 121 arecombined in a cluster, centred on the rotation axis, with tufts ofbristles 115, 125. The tufts of bristles 115, 125 are arranged in aninner polygon of tufts 115, 125 with a central tuft, andcircumferentially between adjacent elastomeric oral hygiene parts 111,121 there are tufts of bristles 115, 125. The circle of elastomeric oralhygiene parts 111, 121 is in each case the radially outermost of theoral hygiene parts on face 104.

The elastomeric oral hygiene parts 111, 121 extend from the face of thebrush part, i.e. in their length direction extending out of the plane ofFIGS. 11 and 12 for ca. 10 mm, and the bristles 115, 125 extend toapproximately the same length. Typically the long dimension of thesection of each strip 112, 122 is ca. 3 mm and the short (thickness)dimension ca. 0.25 mm.

Referring to FIG. 13, a plan view of a face 104 is shown, with radii Rradiating from the rotation axis B-B. A plurality of strips 131 ofelastomeric material is shown in FIG. 13A arranged on a circle centredon the rotation axis, and FIGS. 13B and 13C respectively show a singlestrip 111, 121 of the arrangements of FIGS. 11 and 12. Each elastomericstrips 131, and each of the elastomeric strips 112, 122 which make upthe elastomeric oral hygiene parts 111, 121, is seen in section cutacross the rotation axis and the section is elongated along a longdimension which is aligned at a non-zero, non-perpendicular angle to aradius R intersecting the strip. In each case the angle is ca. 45°.

1. An electric toothbrush comprising a head which is connected to, orreplaceably connectable to, a handle which contains an electric motor,to provide a toothbrush having a head-handle longitudinal direction,wherein the head has: at least one first brush part bearing oral hygieneparts, said first brush part being driveable by the motor in rotarymotion about a first rotation axis generally perpendicular to thelongitudinal direction; and at least one second brush part bearing oralhygiene parts, said second brush part not being driveable by the motorand being capable of limited reciprocal longitudinal motion; wherein thehead contains only one first brush part and only one second brush part,the first and second brush parts being relatively longitudinallydisposed along the head-handle direction, the first brush part beingfurthest from the handle, and the second brush part being adjacent tothe first brush part and closer to the handle when connected to thetoothbrush handle than the first brush part, wherein the second brushpart is enabled to perform limited reciprocal motion by means ofend-stop abutment parts on respectively the head and on the second brushpart, which abut when the second brush part reaches the ends of itslimited reciprocal motion to thereby limit the reciprocal motion.
 2. Thetoothbrush according to claim 1 wherein the second brush part has pinsor sliders on opposite longitudinal sides which slideably engage inrespective longitudinal guides in opposite sides of the head.
 3. Thetoothbrush according to claim 2 wherein the second brush part comprisesa saddle of substantially “C” section which can fit around the head andbe slideably retained on the head.
 4. The toothbrush according to claim2 wherein the longitudinal guides are slots.
 5. The toothbrush accordingto claim 2 wherein the longitudinal guides are grooves.
 6. Thetoothbrush according to claim 1 wherein both of the first and secondbrush parts have oral hygiene parts being bristles mounted thereon,extending from a bristle face thereof.